Extractor means



1970 R.W.1"OWNSENI D 3 I EXTRACTOR animus I Filed Se t. 26. 1966 Ju y-mm m wv um .E, WVIAM w ww T W A H Y B I l I L United States Patent 3,487,733 EXTRACTOR MEANS Ralph W. Townsend, RR. 8, Columbus, Ind. 47201 Filed Sept. 26, 1966, Ser. No. 581,870 Int. Cl. B25b 13/00; B23k 19/10; B23p 19/04 US. Cl. 81-53 8 Claims ABSTRACT OF THE DISCLOSURE An extractor, for extracting an embedded portion of a threaded member such as a bolt which has been broken off at or below the surface. It has a open-ended hollow body-member, with provision for the insertion of an electrode completely therethrough, by which the embedded bolt is Weldable to the wall of the body-member, This, with other co-operating features, provides that bolt-removing torque may be applied to the exposed head of the extractor; and the body-member walls transmit the boltremoving torque to the broken bolt, thus to unscrew it and effect its removal from its embedded position.

This invention relates to an extractor means and process for the removal or extraction of the broken portion of a threaded member, such as a bolt or sparkplug, from a threaded hole of an associated housing or other part into which the threaded member has been screwed.

To avoid repetition, the broken threaded member will be referred to herein usually simply by the term bolt.

Considerable difficulty is presented when a bolt is broken, whether by deterioration such as rust or by the application of too much tightening torque. The extraction or removal of the embedded bolt-portion is usually rendered particularly difiicult when, as often occurs, the bolt has broken below the surface, and the exposed face of the embedded portion is somewhat below the surface of the associated part.

Sometimes, particularly in the situation of a broken sparkplug in a cylinder head, there is no room for the drilling and tapping of another hole; so unless the embedded bolt or plug-portion is removed, without injury to the female threads of the cylinder-head hole, the associated cylinder head must be scrapped, or at least the relatively expensive process of removing the cylinder head is necessary to try to get access to the embedded plugportion from the under side of the head.

Even in other situations, where there is room for ignoring the broken bolt and providing a new threaded opening, other circumstances often make desirable the removal of the embedded bolt for re-use of the existing threaded hole rather than the provision of a new hole, such circumstances including the labor involved, the additional weakening of the part in which a new hole has to be cut, the difficulty of capping over the original hole for reasons such as slightliness, etc. The drilling and tapping of a new hole is often quite inconvenient or timeconsuming.

Known methods of extraction of the embedded bolt generally include the attempt to drill into the embedded bolt-portion, and then inserting some tool into the drilled bolt portion. This, however, is often diflicult to accom- -plish effectively, for sometimes the drill may injure the threads of the opening; and it requires room and access for the drilling. Moreover, certain types of threaded members, such as spark plugs or other threaded ignition means, or bolts which are of a hard nature, cannot be effectively or easily drilled. Further, the drilling process is often complicated by the fact that the bolt has broken off at an angle, making it difficult to get the drill started into the embedded bolt; and this particularly considering the fact that sufficient exactness of alignment of the drill axis with the hole axis is difiicult, also renders more likely the drill slipping or otherwise moving so as to cause injury to the female threads of the associated part.

Moreover, rendering the drill techniqque often ineffective is the fact that the drill tool-bit must be large enough so that the removal will be suflicient capacity to sustain the high removal torque required for extraction of the bolt. This relatively great drill-size often increases the dilficulty and hardship factors mentioned above.

The embedded bolt-portion is often tightly held, for it has usually not deteriorized as has the exposed boltportion which has broken off. The tightness is particularly present when the bolt has been bottomed into the threaded hole, that is, when it has been screwed clear to the bottom of the hole; for, in such a case, there is a compression of the bolt and/or female threads which causes a very tight grip of the embedded bolt.

A cutting out of the entire embedded portion by a process which involves the destruction of the entire hole and of its threads, with a subsequent re-tapping of larger threads and the use of a larger bolt, or the provision of a size-reducing insert to as to attain again the same holesize, has disadvantages which are quite obvious.

Accordingly, the present inventive concepts provide for the extraction of a broken bolt by a welding process using a nipple which freely passes into the threaded openign, a weld being used to secure the nipple to the embedded bolt at the location of the exposed face of the embedded bolt-portion. (Only a relatively small amount of heat is generated, thus the associated female threads are not injured; and it is believed that the small heat actually assists the subsequent removal elfort, for the heat may tend to loosen the binding grip.)

The embedded bolt-portion is then easily removed by applying a twisting effort to the outer portion of the nipple. In situations in which the bolt has broken off substantially flush with the surface, a weld is used to weld the embedded bolt to a nipple-like member magnetically held to the associated part and/or bolt.

The inventive concepts, advantages, features, and other details of the invention are more fully described in the following description of illustrative embodiments of the invention, reference being had to the accompanying somewhat schematic and diagrammatic drawings, in which:

FIG. 1 is a cross-sectional view of an extractor device inserted into a threaded opening of an associated part in which a portion of a broken bolt is embedded, the boltportion having its exposed face below the surface of said part and beneath the outlet of said opening;

FIG. 2 is an elevationalview of the free portion of the broken bolt whose other portion is shown in FIG. 3;

FIG. 3 is a cross-sectional view of the embedded portion of the broken bolt whose free portion is shown in FIG. 2, the embedded bolt-portion being in a threaded opening of an associated part, and with the bolt being broken below the surface of said part and at an angle to the axis of the said threaded opening and to the embedded bolt-portion;

FIG. 4 is a view illustrating the bolt-extractor device of FIG. 1 being cut by an associated grinding tool;

FIG. 5 is a cross-sectional view of the associated part shown in FIG. 3, with the extractor device having been inserted into the threaded opening, in a step of the extraction process;

FIG. 6 is a view similar to FIG. 5 (portions shown as broken away to illustrate interior details), with a weld being applied by an associated welding rod;

FIG. 7 is a view similar to FIGS. 5 and 6, illustrating a more circumferential weld than in FIG. 6, and with an associated wrench applied to the extractor device; and

FIG. 8 is a view, generally in cross-section, of an associated threaded part, and a magnetic extractor device of a type for use in a situation as shown in FIG. 8, in

3 which a bolt is broken off substantially flush with the surface of the associated part.

As shown in FIG. 1, there is provided an extractor for extracting a threaded member shown as the embedded portion 12 of a bolt which has been broken oif below the surface 14 of an associated threaded part 16.

The extractor 10, shown as a body member in the form of a cylindrical nipple 18, whose outer wall is shown of cylindrical form, is of a diameter small enough as to be passable into the threaded opening 22 of the part 16, and down onto the exposed surface of the embedded boltportion 12.

The inner wall 24 of the nipple 18 is shown as tapering inwardly toward its lower end, providing a function yet to be described; and the upper portion of the nipple 18 is provided with an internal sleeve 26, the upper end of which is out-turned to provide an abutment 28 supported by the upper end of the nipple 18, locating the sleeve 26 above the nipple-bottom and preventing the sleeve 26 from being pushed too far downwardly in the nipple 18 during assembly of the sleeve 26 into the nipple 18. The interior 29 of the device 10 is hollow, this hollow interior 29 extending throughout the entire length of the nipple 18.

The convenient and advantageous use of the extractor 10 of FIG. 1 will now be described in connection with FIGS. 2 through 7, in a situation (FIG. 3) in which the embedded bolt-portion 12a is of a bolt which has been broken off below the surface 14 of the associated part 16, and the bolt has been broken off at an angle to the axis of the threaded hole 22 and of the embedded boltportion 12a.

In using the extractor 10 in the aforesaid problem situation (FIG. 3), the extractor nipple 10 is preliminarily held against an associated grinding means 30 (FIG. 4), and the lower end 32 of the nipple 18 is ground away about the same angle and nature as is the angle and nature of the fracture of the open end face 34 of the embedded portion 12a of the broken bolt. If the free portion 12b (FIG. 2) of the broken bolt is available, the fracture-portion 36 of that free bolt-portion 12b is used as a general pattern for the forming or grinding operation, indicated in FIG. 4, to obtain the general contour of the bolt-face 36.

The nipple 18 is then inserted (FIG. 5) into the opening 22 of the associated threaded part 16, in a manner of orientation such that its ground lower end 32 generally registers with the embedded bolt face 34.

Then (FIG. 6), an appropriate associated welding rod 38 is inserted into the free end of the nipple 18 and downwardly through the hollow interior 29; and, depending upon the nature of the situation, (size, tightness, and perhaps other operational factors), a weld in the form of diametrically-spaced tacks or spots 40 (FIG. 6), or a weld 41 of continuous-weld nature (FIG. 7), is applied, securely welding the nipple 18 to the embedded bolt-portion 12a. During the welding operation, the presence of material 42 of the body-member 18, along its exterior, effectively blocks heat from damaging the female hole-threads 22; and the welding process is of such short duration that no weld of the body member to those female threads 22 is made.

The sleeve 26, made of non-conductive material, prevents accidental arcing of the welding rod 38 at a location along the inner wall 24 of the nipple too high for operational reaching of the bolt-surface 34 in the welding process. It will be observed that the lower end 43 of the insulating sleeve 26 is at least substantially as small in diameter as the welding end 32 of the nipple 18, thus guiding the weld-rod 38 toward that nipple location for the welding process.

In a situation of embedded bolts 12a of a small size the welding rod 38 would not ordinarily be positioned in the slanting manner of FIG. 6, but would be positioned generally axially of the nipple 18, the weld being effected peripherally all along the nipple wall 24 substantially simultaneously as the metal of the central portion of the bolt-surface 34 is melted, in contrast to that illustrated diagrammatically in FIG. 6.

Finally in the extraction process, an associated wrench 44 or similar tool is applied to the upper end 46 of the extractor nipple 18, that nipple-end 46 being shown of non-circular (hexagonal as shown) configuration; and twisting manipulation of the wench tool 44 then removes the embedded broken bolt 12a which is secured to the extractor 10 by the foregoing welding.

FIG. 8 illustrates an extractor 50 for use when the embedded bolt-portion is broken off in a manner in which the exposed bolt-surface 34a is substantially flush with or only relatively closely inside of the surface 14 of the associated threaded part 16.

This extractor 50 is shown as having a straight inner wall 52 throughout most of its length, the wall tapering as at 54 to an end 32a which has an end'opening 56 of slightly less diameter than that of the embedded bolt 120. The interior 57 of the extractor 50 is hollow throughout the entire length of the extractor 50.

Magnetic means 58 are provided, shown diagrammatically on the extractor 50 and may be used also on an extractor 10 as shown in FIG. 1; this provides convenient securing of the extractor 50 or 10 to an overhead or other surface :14 of difficult or inconvenient ac cessability, and leaves both hands of the operator free for the welding process.

If desired, locating the extractor 50 may be facilitated by a preliminary marking of the approximate axial center of the exposed bolt-surface.

The exterior of at least a portion of the extractor 50 is non-circular (here hexagonal) permitting use of an associated wrench 44 or similar tool as described above after a weld has been effected, by a weld rod 38 having been thrust through the extractor-interior 57, the weld being effected in the region of the end 32a of the tapered wall 54 and the fractured bolt surface 34a as described above, that is, spot welds at specific peripheral locations (such as indicated in FIG. 6) or a weld continuously along the periphery of the wall-end 32a (such as is indicated in FIG. 7).

The welded combination, of either extractor 10 or 50 with an embedded bolt-portion, is quite strong; for the weld provides a grip of the bolt-portion at portions removed f-rom the bolt-axis, and the extractor walls which eventually sustain and transmit the removal torque are spaced from the extractor axis. Moreover, having been substantially protected from the elements, the embedded bolt-portion is usually strong enough to hold together as a body.

It is thus seen that an extractor means and process, according to the inventive concepts disclosed and described and/or inherent in either form, provides novel and advantageous concepts, features, and operating advantages, including: ease of removal of an embedded portion of a bolt or the like, time and labor saving, reduction of scrapped parts, avoidance of injury to the associated part and its threaded hole, convenience and ease of utility, and the inexpensiveness. A single size extractor will serve for the extraction of bolts of several sizes.

Accordingly, it will be seen from the foregoing description of the invention according to the illustrative embodiments, considered with the accompanying drawings, that the present invention provides a new and useful means and process having desired advantages and characteristics, and accomplishing the intended objects, including those hereinbefore pointed out and others which are inherent in the invention.

Modifications and variations may be effected without departing from the scope of the novel concepts of the invention; accordingly, the invention is not limited to the specific form or arrangement of parts herein described or shown.

What is claimed is:

1. An extraction means for extracting, from an opening of an associated part, the embedded portion of a broken bolt or similar object, said means comprising:

a body member having a first portion for receiving torque effort from an associated tool;

the body member also having a wall means for extending into the said opening of the associated part to integrally operatively engage the exposed surface of the said embedded portion to be extracted, and to sustain removal torque;

the wall means in the region adjacent said exposed embedded-portion surface being weldable to the said exposed surface;

the body member being open-ended and having a hollow core, permitting a welding tool to be inserted through the body member when the body member is positioned in the said opening, and the welding tool to be brought operatively into welding contact with the said exposed surface of said embedded portion and with the said wall means adjacent said exposed embedded-portion surface;

the body member providing integrally (a) said weld- ;able portion of the wall means, and (b) the torqueefiectreceiving portion, and (c) the wall means which integrally extends between and interconnects said potrions, the body member integrally providing means receiving torque effort outwardly of the said associated part opening even when the weldable wall means portion is opreatively engaging the embedded object for weld-removal thereof.

2. The invention as set forth in claim 1 in a combination in which:

the said wall means has an interior surface which is of an operative slanting configuration which provides more material at the end thereof which operatively contacts the said exposed embedded-portion surface.

3. The invention as set forth in claim 1 in a combination in which:

the said first portion of the body member has its exterior portion of non-circular shape to thereby receive removal torque from an associated wrench or similar tool.

4. The invention as set forth in claim 1 in a combination in which:

there is also provided a sleeve means of insulating material which extends throughout a substantial length of the extraction means for guarding against welding effort being applied other than in a location operatively adjacent said exposed embedded-portion surface.

5. The invention as set forth in claim 4 in a combination in which:

the end of said sleeve means closest to the said exposed embedded-portion surface is at least substantially as small in diameter as is the wall means in the region of the wall means adjacent said embeddedportion surface.

6. The invention as set forth in claim 1 in a combination in which:

the body member has material outwardly of the portion weldable to the said exposed surface, protecting the walls of said associated part opening from the welding process.

7. An extraction means for extracting, from an opening of an associated part, the embedded portion of a broken bolt or similar object, said means comprising:

a body member having a first portion for receiving torque effort from an associated tool; and the body member having a second portion adapted to be placed immdiately adjacent the exposed surface of said embedded portion and to be Welded thereto;

the body member having a hollow core permitting an associated welding tool to be passed operatively therethrough, from the end thereof remote from said embedded portion, to the end thereof adjacent said embedded portion;

the inner walls of said body member which define said core being of non-uniform cross-sectional shape, being of greater spacing remote from said embedded portion than adjacent thereto, providing both cease of passing said associated welding tool to the portion thereof to be welded to said embedded portion and also the minimizing of chance that a Weld will be inadvertently made to said body member operatively remote from said embedded portion.

8. The invention as set forth in claim 1 in a combination in which the said body member carries magnetic means causing it to operatively adhere to said associated part and/ or to said embedded portion.

References Cited UNITED STATES PATENTS 2,154,654 4/1939 Armentrout et al. 219107 X 2,218,131 10/1940 Gipson et al 219-107 X 2,391,405 12/1945 Fuglie 29426 X 3,279,047 10/ 1966 Cumberland 29427 3,033,144 5/ 1962 Schmidt. 3,195,380 7/1965 Bicks 813.8

JOHN F. CAMPBELL, Primary Examiner D. C. REILEY, Assistant Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,487,733 January 6, 1970 Ralph W. Townsend It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below: Column 1, line 55, "slightliness" should read sightlines Column 2, line 3, "techniqque" should read technique line 5, after "be" insert of line 10, "deteriorized" shou read deteriorated line 25, "openign" should read openi Column 3, line 51, "situation," should read situation Column 4, line 10, "foregoing" should read aforesaid line 60, before "inexpensiveness" cancel "the". Column 5, line 27, "potrions" should read portions line 30, "opreatively" should read operatively Column 6, line 18, "immdiately" should read immediately line 28, "eease" should read ease (SEAL) Signed and sealed this 17th day of November 1970 Attest:

Edward M. Fletcher, Ir. WILLIAM E. SCHUYLER, JR Attesting Officer Commissioner of Patents 

